Project Summary/Abstract: Major gaps exist in our knowledge of the health impacts of widespread and dramatically expanding exposures among children in the US. Children from rural regions are particularly understudied, but may experience higher exposures to contaminants by drinking unregulated water; from household air pollution from wood stoves; and consequent to their rural and changing landscape (e.g., from climate change). As part of this ECHO Pediatric Cohorts application, we propose to take advantage of the NIEHS/EPA supported New Hampshire Birth Cohort Study (NHBCS): a rural, ongoing pregnancy cohort that has accrued over 1,500 maternal-infant dyads. By the beginning of the UH3 phase of this application, the anticipated cohort size will be 2,000, and as part of this ECHO Pediatric Cohorts application, accrual will be extended to 3,000 maternal-infant pairs. Clinical outcomes are being ascertained from interval interviews, questionnaires, medical records, in-person assessments and laboratory tests. The study has archived environmental (tap water and indoor air) and biological samples collected during pregnancy (maternal blood, urine and hair), as well as biological samples acquired at birth (infant cord blood, placenta and meconium) and during childhood (urine, blood, buccal cells, breast milk, toenails and stool). With support of a state-of-the-art biorepository, the ability to utilize these samples for a wide range of downstream analyses has been demonstrated, e.g., for DNA methylation arrays, gene expression, microbiome sequencing, metabolomics and flow cytometry. For the current application, emerging hypotheses of concern will be addressed by: (1) leveraging the extant NHBCS to perform targeted and unsupervised metabolomic analyses of 1,000 cord blood samples and 250 paired maternal gestational blood samples, and assess associations with exposures, early growth, and the infant microbiome; (2) expanding data acquisition, sample collection and participant accrual to more precisely characterize exposures and timing of early life exposures by obtaining urinary metallome and metal metabolomic measurements, and exposome monitoring data from the first trimester of pregnancy, along with spatial analysis of naturally shed teeth for prenatal metal concentrations; and (3) extending follow-up to identify childhood exposures to contaminants (through biomarkers and personal monitors); the home environment (e.g., physical activity and sleep patterns, food environment, green, blue and white space, and media usage); and medical exposures (e.g., prescription and non-prescription medications and surgical interventions) that relate to fetal and childhood growth, obesity at age 3 years, respiratory infection and asthma by age 5 years, and pulmonary function data at age 7.5 years. Additionally, novel statistical approaches will be used to determine the role of the intestinal and salivary microbiome as mediators of these effects. The collective expertise, methodologies, data, samples and preliminary results from this study will contribute to the planning of the broader ECHO Pediatric Cohorts initiative in order to advance our understanding of the environmental factors early in life that drive childhood and lifelong health.